Disease Note

Botrytis porri on Leek in Canada. S. K. Asiedu, Macdonald College of McGill University, Ste. Anne de Bellevue, Que., Canada H9X 1C0. G. S. V. Raghavan, Y. Gariepy, and R. Reeleder, Macdonald College of McGill University, Ste. Anne de Bellevue, Que., Canada H9X 1C0. Plant Dis. 70:259. Accepted for publication 22 November 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-259c.

Leek (Allium porrum L. ‘Alaska’ and ‘Furare’) grown at Laval, Que., in 1984 developed rot during 5 mo of storage in conventional and controlled atmosphere systems (2–3% CO₂ + 4–8% O₂) at 1.5 C. The most characteristic symptoms were pale brown, water-soaked lesions on the adaxial surface of leaves, usually in the blanched areas and the pseudostem. Occasionally, irregular white lesions were noted on the leaves. The pathogen was isolated on potato-dextrose agar, where only mycelium and sclerotia (2–8 mm long) were produced. Conidia 8–20 × 4–16 μm (mean, 11.3 × 8.4 μm) were produced within 15 days at 21 C on Czapek agar under continuous cool-white fluorescent light. Rot developed in 8 days on leek and onion samples inoculated with the isolates of the pathogen in humid chambers at 21 C. The pathogen was identified as Botrytis porri Buchw.; identification was confirmed by W. R. Jarvis, Agriculture Canada Research Station, Harrow, Ont. In North America, B. porri has been reported recently on garlic grown in California, Nevada, and Oregon. We report for the first time B. porri rot on stored leeks in Canada.